How to disable all connection pooling in Spring Boot?

Question

Context

By default our SpringBoot application uses HikariCP for its connection pooling.

We are currently investigating how to increase the performance of our application, and want to check out how our load tests behave when using PgPool instead.

It is our understanding that HikariCP and PgPool will not work well with each other and thus that we should be able to disable HikariCP in order to test the performance when using PgPool appropriately.

Question

How does one ensure that no connection pooling ("CP") is used at all at the application level?

Precision

The ultimate goal being to plug PgPool in between our application and our database.

It's my (potentially flawed) understanding that HikariCP should be disabled for that, and that each getConnection() call should return a new connection fetch from the JDBC URL configured for our application. And that that JDBC URL should eventually point to PgPool instead of the DB, which will take care of returning pooled connections.

Attempts

First, we simply removed Hikari from the dependencies:

configurations.all { exclude group: 'com.zaxxer' }

But we'd get this error:

Error starting ApplicationContext. To display the conditions report re-run your application with 'debug' enabled.]
13:04:34.0242 - ERROR   TenantId[]  UserId[]    TraceId[]   Thread[main]
                Logger[org.springframework.boot.SpringApplication]
                Msg[Application run failed]
org.springframework.context.ApplicationContextException: Unable to start web server; nested exception is org.springframework.boot.web.server.WebServerException: Unable to start embedded Tomcat
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:163)
    at org.springframework.context.support.AbstractApplicationContext.refresh(AbstractApplicationContext.java:577)
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.refresh(ServletWebServerApplicationContext.java:145)
    at org.springframework.boot.SpringApplication.refresh(SpringApplication.java:754)
    at org.springframework.boot.SpringApplication.refreshContext(SpringApplication.java:434)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:338)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1343)
    at org.springframework.boot.SpringApplication.run(SpringApplication.java:1332)
    at com.sap.s4hana.eureka.business.centralinventory.application.Application.main(Application.java:17)
Caused by: org.springframework.boot.web.server.WebServerException: Unable to start embedded Tomcat
    at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.initialize(TomcatWebServer.java:142)
    at org.springframework.boot.web.embedded.tomcat.TomcatWebServer.<init>(TomcatWebServer.java:104)
    at org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory.getTomcatWebServer(TomcatServletWebServerFactory.java:450)
    at org.springframework.boot.web.embedded.tomcat.TomcatServletWebServerFactory.getWebServer(TomcatServletWebServerFactory.java:199)
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.createWebServer(ServletWebServerApplicationContext.java:182)
    at org.springframework.boot.web.servlet.context.ServletWebServerApplicationContext.onRefresh(ServletWebServerApplicationContext.java:160)
Caused by: org.springframework.boot.web.server.WebServerException: Unable to start embedded Tomcat

    ... 8 common frames omitted
Caused by: org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'webMvcMetricsFilter' defined in class path resource [org/springframework/boot/actuate/autoconfigure/metrics/web/servlet/WebMvcMetricsAutoConfiguration.class]: Unsatisfied dependency expressed through method 'webMvcMetricsFilter' parameter 0; nested exception is org.springframework.beans.factory.BeanCreationException: Error creating bean with name 'prometheusMeterRegistry' defined in class path resource [org/springframework/boot/actuate/autoconfigure/metrics/export/prometheus/PrometheusMetricsExportAutoConfiguration.class]: Initialization of bean failed; nested exception is org.springframework.beans.factory.UnsatisfiedDependencyException: Error creating bean with name 'healthRegistryCustomizer' defined in class path resource
...(I interrupt the stacktrace there due to company policy)
nested exception is java.lang.IllegalStateException: No supported DataSource type found

I eventually got around to adding the following to our dependencies:

implementation 'org.apache.tomcat:tomcat-jdbc:10.0.14'

But then I'm left wondering:

1. Does Tomcat enable CP by default? (Which would thus mean I have not effectively removed application-level CP)
2. Is there not a way to simply add a configuration in application.properties to keep the servlet container but avoid CP? (So that I don't need to remove Hikari from the dependencies.)

I also tried adding (inspired by this SO answer):

spring.datasource.type=org.springframework.jdbc.datasource.DriverManagerDataSource
spring.datasource.driver-class-name=org.postgresql.Driver

And also tried replacing that DriverManagerDataSource with SimpleDriverDataSource, but to no apparent avail since I cannot seem to confirm that indeed no CP is used.